On Tue, 2009-05-26 at 09:21 +0300, Brocha Strous wrote: > Is the following line valid: > > a=rtpmap:101 telephone-event/000 > > What is the meaning of a 0 clock rate? And isn't it supposed to be a > number? I tried to find somewhere a BNF specification for RTPMAP > attribute lines but only found very general statements. What would be > the correct way to parse a RTPMAP line into all its pieces that would > account for the different syntaxes? Should the clock rate be treated > as a string and not a number?
Looking at RFC 2833, especially section 3.5, the "rate" part of the rtpmap specification means that the time units in the RTP telephone-event packets are at that many per second. E.g., the standard value "8000" means that the timestamps are in units of 1/8000 second. Given that, a rate value of zero is useless. In your case, the standard value is 8000, and what we see is "000", making it extremely likely that the line you see is a typo for a=rtpmap:101 telephone-event/8000 Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
